Spring Security Build modules using Java 8

We should use Java 8 to build our modules since we have to be Java 8 compatible.

As of now, there is no way to know if we added a Java 9+ language feature.

We might use Gradle Toolchain in order to specify a Java version to run the tasks

Comment From: marcusdacoregio

Fixed via https://github.com/spring-projects/spring-security/pull/10817